#!/usr/bin/perl -w

 sub sum (@) {
 # This subroutine takes a list of numbers as input
 # and returns the sum
 my $sum = 0;
 for my $tmp (@_) {
 $sum += $tmp;
 }
 return $sum;
 }

 # calculates 0 + 1 + 2 + ... + 100 and prints the value
 print sum 0 .. 100; # must be 5050. No doubt.